What A Dancing Sea Lion Can Tell Scientists About The Biological Roots Of Human Rhythm

A beat-keeping sea lion sheds insight about how human rhythm came to be. Photo: C. Reichmuth

It was once thought that homo sapiens were the only creatures on the planet with the ability to get their dance moves on and respond to music. This notion was shattered in 2009 when a cockatoo was able to dance along to pop songs, proving that non-humans can process rhythmic stimuli.

Since then, other specimens (e.g. chimps, bonobos, parrots, budgerigars) have joined the exclusive club of creatures that can move to music and now, a Californian sea lion named Ronan has joined the group. While the sea mammal’s head-bobbing ability is amusing to watch, it is serves a more practical purpose by giving scientists insight about human rhythm and how it evolved.

The research team, which published their findings on the open-access academic publishing platform Frontiers in Neuroscience, wanted to explore the biological roots of musicality. Peter Cook and Andrew Rouse from the University of California, Santa Cruz spent time with Ronan, a sea lion placed into captivity at the age of one after being rescued from the wild, on the weekends. Every time Ronan successfully kept up with a beat, she would receive fish treats.

Ronan, who has a preference for Earth, Wind and Fire's Boogie Wonderland, is said to keep up with music better than any other non-human animal. After several experiments to confirm that Ronan was responding to music and not arbitrarily bobbing around, Rouse and Cook published their preliminary findings in 2013.

"A lot of the work that has been done on beat-keeping in general—to show whether a person or an animal is entrained—has used an observational approach, which looks at how close the animal is to each individual beat," says Rouse, adding that these studies "don't reveal any underlying cause."

To further understand what allows Ronan to keep up with different tune, Rouse and Cook expanded on their initial findings. They got Ronan to move to a beat, changed the tempo or phase of the rhythm, and watched to see how she adapted to the new beat. The researchers tracked her movements to identify when she recalibrated her moves.

Ronan’s ability is unique since all previous animals that have shown an ability to keep up with music have “vocal flexibility,” but sea lions are not vocal mimics. This opens up the possibility, contrary to previous theories, that the neural circuits required to keep up with music are independent from those needed for vocal flexibility. Rouse notes that more exploration is required to make confirmed claims.